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Giant flywheel project in Scotland could prevent UK blackouts

theguardian.com

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Re: Giant flywheel project in Scotland could prevent UK blackouts

#61

Post by bob1029 »

Ballas wrote: post #10
_whiteCaps_ wrote: post #4

> This is the first time a project of this kind will be used anywhere in the world and ESO believes it could be a “huge step forward” in running a zero-carbon electricity grid. I'm trying to find some stats on this, because flywheel UPS aren't a new idea: https://www.finning.com/en_IE/products/new/power-systems/ele... https://en.wikipedia.org/wiki/Flywheel_storage_power_system#...

What is different in this case is it is not really an energy storage system (at least that is not the main intended purpose), but only to provide stability to the grid frequency. A huge flywheel in a vacuum to provide a reference to millions of distributed PLLs. I don't think the idea is to always have it spin at a fixed rate with minimal losses. In the case where a flywheel is used as a UPS, the rate at which it is…

The point here is that the flywheel is so massive that the amount of energy required to bring it below (or above) the allowable frequency range is practically very large.

Large steam/gas turbines running on the grid have a similar effect. Even without hot gas running through them, they can provide rotational inertia for grid stabilization purposes. This flywheel is basically an extremely heavy version of the same idea, and powered exclusively by the grid itself.

You wont be able to ride out a scenario where there is a long-term lack of generation capacity, but this flywheel could buy the precious seconds/minutes required to spin up peaker plants and other contingencies.

Re: Giant flywheel project in Scotland could prevent UK blackouts

#62

Post by tpmx »

msandford wrote: post #42
tpmx wrote: post #39

Earlier quoted context omitted.

What happens if the grid frequency disagrees too much with the rotation frequency of the flywheel, too quickly? The flywheel disintegrates and turns into a massive spherical weapon of mass distruction? Like this, but 20x worse? https://www.youtube.com/watch?v=bdcE3VyKv5U

The spinning flywheel doesn't just spin on its own. It gets spun up and kept spinning by an electric motor/generator I have to imagine. So you're limited as to how much power can go in or out by the size of that motor/generator. If it's a 100kw peak electrical machine then it can provide at most 100kw of instantaneous power to the grid while at the same time slowing down by however much is required to deliver that po…

Sorry, but this comment shows that you don't understand the physics that would be involved in something like this.

Re: Giant flywheel project in Scotland could prevent UK blackouts

#63

Post by lettergram »

_whiteCaps_ wrote: post #4

> This is the first time a project of this kind will be used anywhere in the world and ESO believes it could be a “huge step forward” in running a zero-carbon electricity grid. I'm trying to find some stats on this, because flywheel UPS aren't a new idea: https://www.finning.com/en_IE/products/new/power-systems/ele... https://en.wikipedia.org/wiki/Flywheel_storage_power_system#...

I remember back in the early 2000’s my father was investing in a company building a flywheel. They were working on installing one in New York, not really sure what happened but I believe they installed one or two before the company went bust.

Re: Giant flywheel project in Scotland could prevent UK blackouts

#65

Post by hinkley »

tankenmate wrote: post #34
Ballas wrote: post #10

Earlier quoted context omitted.

What is different in this case is it is not really an energy storage system (at least that is not the main intended purpose), but only to provide stability to the grid frequency. A huge flywheel in a vacuum to provide a reference to millions of distributed PLLs. I don't think the idea is to always have it spin at a fixed rate with minimal losses. In the case where a flywheel is used as a UPS, the rate at which it is…

You can get constant spin rate but variable energy storage / release by adjusting the moment of inertia, e.g. if you have movable weights within the rotor you can move these inboard or outboard, moving it inboard uses energy while increasing the spin rate, and moving it outboard releases energy while slowing the rate. Using this in combination with "conventional" direct axle energy input / release means you can store…

You've seen what your washing machine does when you get a blanket off-balance in it.

Imagine if one of the motors on the flywheel stopped responding to inputs.

Windmills had governors which were horizontal wheels with two or more pendulums attached to the outer edge. The angular velocity is trying to lift the pendulum and gravity is pushing it back down, so velocity increases much slower than momentum.

The only problem you need to worry about there is seized bearings or foreign bodies unbalancing the load.

There are other devices that replace gravity with springs. You might be able to do the same with permanent magnets. But I believe each of these relies on the device being able to put up with larger strains than the pendulum.

Re: Giant flywheel project in Scotland could prevent UK blackouts

#66

Post by jimnotgym »

DrBazza wrote: post #27
happytoexplain wrote: post #19

Earlier quoted context omitted.

>The rest of the world just builds a dam, creates a new lake, and moves on. Your wording implies this is better than the flywheel solution - can you elaborate for a layman?

I'm just cynically generalising - the rest of world compared to the UK has typically less stringent planning requirements, and more mountainous terrain. To store energy in other countries (except perhaps Holland..!) you build a hydro dam, and pump water into those dammed lakes using excess electricity to store it up for later release. We have mountains (Wales, Lake District, Scotland), but the likelihood of creating…

There are two pumped storage stations in Wales that I know of. Dinorwig (where the power station is inside the mountain, as a student I got to go in there) and Ffestiniog. Wales has a long history of having dams built to provide water to English cities, see the Elan Valley, Llyn Vyrnwy, Llyn Clewedog and many more. The displacement of people and 'theft' of water even spurned a terrorist organisation to stop it called the Free Wales Army!

Re: Giant flywheel project in Scotland could prevent UK blackouts

#67

Post by jillesvangurp »

URSpider94 wrote: post #44
xhkkffbf wrote: post #32

Why do we care about keeping frequency stable when more and more products simply put the power through a rectifier to turn it to DC? The lamps all have LED "bulbs". The computers have power bricks. Do we really care if the compressors in the air conditioners and the refrigerators turn at a slightly different rate? Okay, maybe a rapid shift in frequency could be damaging, but a slight drift sounds okay mechanically. O…

In the electrical grid, frequency is proportional to voltage. When the frequency drops, it means that the supplied voltage is also falling. Likewise, if you go over-frequency, then the voltage will rise. Traditionally, the inertia of thousands of tons of spinning generator turbines across the system provided this inertia, but with more and more nonlinear sources (and also nonlinear loads), that balance is disappearin…

Batteries are also becoming popular for the same reason. The more batteries you have the easier it is to deal with fluctuations in supply and demand as you can switch them on and off in milliseconds and they can serve to both supply GW to the grid or absorb it from the grid.

Flywheels are useful because they store a lot of energy and don't require a lot of energy to keep them spinning (i.e. topped up with energy). Simply connecting them to a generator can be done (relatively) quickly and allows them to supply power for a relatively long period of time. It's basically a mechanical battery.

Both have the advantage that they are cheaper to operate than a typical peaker plant, which is increasingly the role of remaining coal plants that are otherwise too expensive by orders of magnitudes to operate continuously. Switching those on is a last resort for energy companies. The more battery they have, the less need they have for those. And the less they get utilized, the more expensive they are to keep around. Gas plants are better but they take a long time to turn off and on again and doing that is also not cheap.

Prices have actually turned negative a couple of times in e.g. the UK in cases where the power companies were literally paying people to use their excess power just so they could avoid having to turn off plants that are expensive to turn back on. Basically, grid storage capacity allows electricity companies to smooth out peaks in demand and supply and respond extremely rapidly by either soaking up or supplying many GW.

Re: Giant flywheel project in Scotland could prevent UK blackouts

#68

Post by TremendousJudge »

bob1029 wrote: post #61
Ballas wrote: post #10

Earlier quoted context omitted.

What is different in this case is it is not really an energy storage system (at least that is not the main intended purpose), but only to provide stability to the grid frequency. A huge flywheel in a vacuum to provide a reference to millions of distributed PLLs. I don't think the idea is to always have it spin at a fixed rate with minimal losses. In the case where a flywheel is used as a UPS, the rate at which it is…

The point here is that the flywheel is so massive that the amount of energy required to bring it below (or above) the allowable frequency range is practically very large. Large steam/gas turbines running on the grid have a similar effect. Even without hot gas running through them, they can provide rotational inertia for grid stabilization purposes. This flywheel is basically an extremely heavy version of the same ide…

How much mass are we talking about here? I'm curious and the article doesn't give any numbers. Order of magnitude at least?

Re: Giant flywheel project in Scotland could prevent UK blackouts

#69

Post by ladberg »

tpmx wrote: post #62
msandford wrote: post #42

Earlier quoted context omitted.

The spinning flywheel doesn't just spin on its own. It gets spun up and kept spinning by an electric motor/generator I have to imagine. So you're limited as to how much power can go in or out by the size of that motor/generator. If it's a 100kw peak electrical machine then it can provide at most 100kw of instantaneous power to the grid while at the same time slowing down by however much is required to deliver that po…

Sorry, but this comment shows that you don't understand the physics that would be involved in something like this.

I think you're misunderstanding how this flywheel operates. It doesn't provide 50hz AC in the same way the grid operates, it just is attached to a DC motor that provides electricity which can then be converted into AC to power the grid.

That means it can spin at any frequency and it doesn't really matter what state the grid is in.

Re: Giant flywheel project in Scotland could prevent UK blackouts

#70

Post by grey-area »

DrBazza wrote: post #8

This is a consequence of the UK having little capacity for pumped-storage, i.e. hydro-electric. We don't really have the height, and we have "areas of outstanding natural beauty" that cannot be built in easily, so we need alternatives to store the energy. The rest of the world just builds a dam, creates a new lake, and moves on.

Scotland has quite a lot of hydro schemes that could be used as pumped storage and 2 large projects planned.

Balmacaan and Coire Glas are in the planning stages and due to start building soon. There's plenty of high land available.

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